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A study of sonochemically synthesized ZnS:Mn nanoparticles is presented. The particles prepared at low rf power (about 20 W) and room temperature coalesce to form morphologically amorphous large species (30-100 nm in diameter). As the power is increased in the range from 20 to 70 W, and the solution temperature is raised to 60 to 80 degrees C, finer particles are produced with the size ranging from 2 to 20 nm and improved crystallinity. The results indicate the dispersion of the Mn(2+) ions at near-surface sites in the particles. It is shown that the sonochemically fabricated particles approach the quality of the ones obtained by a standard chemical route and show a reasonable luminescence performance.

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The initial oxidation of Zr1Nb alloy in oxygen, water and hydrogen peroxide at room temperature has been studied by angle-resolved x-ray photoelectron spectroscopy (ARXPS). The clean surface of alloy has been prepared either by scraping under ultrahigh (10 −10 mbar) vacuum or by argon ion sputtering.The four well-defined oxidation states of Zr were identified in the oxide films on Zr1Nb. The results of the ARXPS study were consistent with a layered structure of the oxide film, with zirconium dioxide in the outermost part of the film and suboxides in the inner region. The overall thickness of the incipient oxide layers ranged from 1.8 nm for the sputtered surface oxidized by oxygen, to 4.2 nm for the scraped surface oxidized in hydrogen peroxide. Mathematical analysis of the fitted Zr 3d spectra based on a layered structure model allowed us to estimate the thicknesses of individual suboxide layers. The population of suboxides as well as the binding energy of the Zr 3d electrons belonging to tetravalent zirconium were found to depend on the oxidizing agent and on the method used to clean the surface prior to oxidation. The amount of suboxides was much higher on the oxidized alloy surface cleaned by ion sputtering than on surfaces cleaned by scraping. The presence of zirconium hydride was observed in the spectra of Zr 3d electrons of the samples oxidized by water. The observed differences in binding energy of the Zr 3d component assigned to the Zr 4+ oxidation state are interpreted by differences in the structure of the dioxide layer.